Pachmayr Mag Spacer, Grip Extension, Black, Adapt Full-Size Magazines For Use With Compact Handguns, For Glock 20/21 Mags 3853 Pachmayr Mag Sleeves adapt full-size magazines for use with compact handguns in many popular models. Mag Sleeves allow you greater shooting capability by increasing the gun's grip size and capacity with additional rounds. Carry your compact pistol with a standard magazine when concealment is important" or insert a high capacity magazine fitted with your Pachmayr Mag Sleeve when the situation calls for it. Mag Sleeves simply slide over the magazine and fit securely in place. Improve the handling and performance of compact handguns with Pachmayr Mag Sleeves.